1. Field of the Invention
The present invention relates to drawing of a machining configuration, and more particularly, to a drawing apparatus for and a drawing method of displaying a machining configuration in an electric discharge machine.
2. Description of the Related Art
In wire electric discharge machines, a machining configuration is drawn on a screen to confirm the contents of a machining program and a present machining position.
When the machining configuration is displayed on the screen, a part of a machining path may be displayed thereon in enlargement to confirm the detailed configuration of a present machining position depending on a configuration and a size to be machined, in addition to the case where an overall machining configuration is displayed on the screen.
When a part of the machining path is displayed, the present machining position may run off the machining path on the screen on which the present machining position is displayed in enlargement as machining proceeds. In this case, a region in which the present machining position is displayed in enlargement must be set again and the present machining position must be displayed again. An operation for setting and displaying the enlarged display area again imposes a burden on an operator in addition to an operation for machining, due to which an operating efficiency is deteriorated.
It is contemplated to set an area to be displayed on the screen in a large size as a countermeasure for making the operation for an enlarged display unnecessary. When the dimension of the region to be displayed is increased, the number of times of enlarging and displaying the present machining position again can be reduced. However, since the resolution of display on the screen is lowered thereby, the present machining position and the machining configuration are displayed in a small size, which makes it difficult to confirm details.
Japanese Patent Application Laid-Open No. 06-262436 discloses a method of updating a display area to be drawn on a screen. According to the method, a portion from the leading end of an NC program to a work replacement code or a pallet replacement code included in the NC program or a portion from a previous work replacement code or a previous pallet replacement code included in the NC program to a next work replacement code or a next pallet replacement code is recognized as a portion. Then, an optimum scale value in each portion is calculated, and a movement locus is displayed according to the calculated scale value.
In the display area update method, a display magnification is changed by calculating a scale value each time a code set to the NC program is changed. Accordingly, even if the display magnification need not be changed because the amount of change of a machining position is small, a display is changed by the display magnification according to a scale value calculated again. Accordingly, a problem arises in that it is difficult to confirm a present machining position because the display magnification is changed frequently, in addition to a problem that an amount of calculation processing is increased.
Japanese Patent Application Laid-Open No. 09-120308 discloses another method of updating a display area to be drawn on a screen. In the method, a plurality of partial machining regions, which are to be displayed in enlargement, are previously set before a tool movement path begins to be drawn. After the tool movement path begins to be drawn, a partial machining region to which a tool position belongs is automatically switched and displayed on a screen in enlargement according to a tool moving position. The tool movement path is drawn in the partial machining area shown on the screen in enlargement. As a result, a plurality of previously set partial machining regions can be automatically drawn without manually switching them.
The display area update method is disadvantageous in that a setting workload is increased because the partial machining regions must be previously set. In particular, when a tool movement position is changed complexly, and when a tool moving path is long, the setting workload increased, thereby an operation efficiency is lowered.
Further, since display magnifications are previously set as a program or items to be set, a problem arises in that it is difficult to set the display magnifications for each operator or for each machining.